如何从 foreach 循环创建关联数组？答案

【问题标题】：How can I create an associative array from a foreach loop?如何从 foreach 循环创建关联数组？
【发布时间】：2016-09-09 20:59:48
【问题描述】：

$array = ["farm"=>
              [
                "horse"=>
                 [
                  "rabbit"=>
                     [
                      "fred1"=> "fred1",
                      "fred2"=> "fred2",
                      "fred3"=> "fred3",
                      "fred4"=> "fred4"
                    ],
                 "raccoon"=>
                    ["frida"=> "frida"]
                  ]  
              ]
    ];

我想为每个循环创建一个数组：

$keySearch = "o";

    function createList($array, $keySearch, $path) {
        foreach ($array as $key => $item) { 
            $basePath = $path === null ? $key : $path. "/" . $key;
               if(is_array($item)){
                  if (stripos($key, $keySearch) !== false){
                     $a['key'] = $key ;
                     $b['basePath'] = $basePath;
                     $result[] = array_merge_recursive ($a, $b);            
                  }
                 createList($item, $keySearch, $basePath);
                }       
        }
    print_r($result);
    }
    createList($array, $keySearch, '');

我的结果是：

Array
(
    [0] => Array
        (
            [key] => horse
            [basePath] => farm/horse
        )

)
Array
(
    [0] => Array
        (
            [key] => raccoon
            [basePath] => farm/horse/raccoon
        )

)

我真正期望的是：

 Array
    (
        [0] => Array
            (
                [key] => horse
                [basePath] => farm/horse
            )
        [1] => Array
            (
                [key] => raccoon
                [basePath] => farm/horse/raccoon
            )

    )

https://eval.in/571065

【问题讨论】：

你的预期输出有什么区别？
@splash58 我的输出是两个数组，但我只需要一个数组
什么是 $keySearch ？
这里是$keySearch = "o"
为什么 john 不在结果中？

标签： php arrays multidimensional-array associative-array

【解决方案1】：

递归算法解决方案：

    <?php

        $array = ["farm"=>
              [
                  "horse"=>
                  [
                      "rabbit"=>
                          [
                              "fred1"=> "fred1",
                              "fred2"=> "fred2",
                              "fred3"=> "fred3",
                              "fred4"=> "fred4"
                          ],
                      "raccoon"=>
                          ["john"=> "john"]
                  ]
              ]
        ];


            $jl     = array();
            $root   = "";

            function walkJarLarsData($ar, $search, $base="base-path", $pKey=""){
                global $jl, $root;
                if(!stristr($root, $base)){
                    $root  .= $base;
                }

                foreach($ar as $key=>$val){
                    $pKey       = $pKey?"{$pKey}":"";
                    if (preg_match("#" . preg_quote($search) . "#", $key)) {
                        $jl[]   = array(
                            "key"       => $key,
                            "basePath"  => $root . "/{$pKey}/{$key}",
                        );
                    }
                    if(is_array($val)){
                        walkJarLarsData($val, $search, $base, $key);      
                    }
                }


                return $jl;
            }

            var_dump(walkJarLarsData($array, "o"));

【讨论】：

【解决方案2】：

我改进了你的代码：

 function createList($array, $keySearch, $path=null) {
    $result = [];
    foreach ($array as $key => $item) { 
        $basePath = $path === null ? $key : $path. "/" . $key;
           if(is_array($item)){
              if (stripos($key, $keySearch) !== false) {
                 $result[] = ['key' => $key, 'basePath' => $basePath];            
              }
             $result = array_merge($result, createList($item, $keySearch, $basePath));
            }       
    }
return $result;
}

$keySearch = 'o';
$res = createList($array, $keySearch);
print_r($res);

demo

UPD：如果您找到所有键，而不仅仅是那些指向数组的键，请更改代码：

function createList($array, $keySearch, $path=null) {
              $result = [];
    foreach ($array as $key => $item) { 
        $basePath = $path === null ? $key : $path. "/" . $key;
        if (stripos($key, $keySearch) !== false)
             $result[] = ['key' => $key, 'basePath' => $basePath];            
        if(is_array($item))
             $result = array_merge($result, createList($item, $keySearch, $basePath));
    }
return $result;
}

$keySearch = 'fr';
$res = createList($array, $keySearch);
print_r($res);

demo

【讨论】：

例如，如果数组中有key=>value，则不会被第1个代码选中，会被第2个，。但是 $key=>[array] 在这两种情况下都会出现

【解决方案3】：

您可以将相同的函数与添加 ref 属性一起使用，并将数组附加到该属性中。

$array = ["farm"=>
              [
                "horse"=>
                 [
                  "rabbit"=>
                     [
                      "fred1"=> "fred1",
                      "fred2"=> "fred2",
                      "fred3"=> "fred3",
                      "fred4"=> "fred4"
                    ],
                 "raccoon"=>
                    ["frida"=> "frida"]
                  ]  
              ]
    ]; 

function createList($array, $keySearch, $path, &$out) {
    foreach ($array as $key => $item) { 
        $basePath = $path === null ? $key : $path. "/" . $key;
        if(is_array($item)){
            if (stripos($key, $keySearch) !== false){
                $a['key'] = $key ;
                $b['basePath'] = $basePath;
                $out[] = array_merge_recursive ($a, $b);            
            }
            createList($item, $keySearch, $basePath, $out);
        }       
    }
}

$keySearch = "o";
createList($array, $keySearch, '', $result);
print_r($result);

演示：https://eval.in/571224

【讨论】：

【解决方案4】：

当然，这就是您寻求的解决方案：

<?php

    $arBase     = array();
    $kern       = "";

    function arrayRecurse($ar, $search, $mainPath="base-path", $cue=""){
        global $arBase, $kern;
        $kern   = !(stristr($kern, $mainPath))? $kern.= $mainPath : $kern;

        foreach($ar as $key=>$val){
            $cue       = $cue?"{$cue}":"";
            if (preg_match("#" . preg_quote($search) . "#", $key)) {
                $arBase[]   = array(
                    "key"       => $key,
                    "basePath"  => $kern . "/{$cue}/{$key}",
                );
            }
            if(is_array($val)){
                arrayRecurse($val, $search, $mainPath, $key);
            }
        }

        return $arBase;
    }

    var_dump(arrayRecurse($array, "fr"));

【讨论】：